Effects of several plant growth regulators, carbon source and amino acids on somatic embryos obtained from embryogenic cell suspension cultureof alfalfa (Medicago sativa L.)

Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world that have a significant role in forage supplying, nitrogen fixation and reduction of soil erosion. The species is self-incompatible and cross pollinate, so maintenance and propagation of desired genotypes are difficult and production of pure and hemogeneous seeds is faced with difficulties.Somatic embryogenesis is one of the most useful techniques that can help us to solve theproblems. Therefore, recognition of the affecting factors on somatic embryogenesis isimportant. This study was aimed to evaluate the effects of two growth regulators, 2,4-D (0.5 and 1 mgL-1) and Kinetin (0 and 1 mgL-1), carbon source (sucrose and maltose) and Glutamine and Serine as amino acids, on alfalfa somatic embryogensis in an embryogenic cell suspension culture using 4 explants (hypocotyl, cotyledon, petiole and leaf). The treatments showed significant differences. There was a correlation between 2,4-D concentration and the number of embryos in maturity stage, so that increasing the concentration of 2,4-D resulted in lower number of embryos. Presence of Kinetin in the culture media increased number of somatic embryos, significantly. Despite significant effects of Glutamine and Serine on embryo development, application of these amino acids in suspension culture media decreased the regeneration of somatic embryos in the liquid cultures. Maltose in liquid culture was the most effective agent on the maturity of somatic embryos and increased the number of embryos in embryogenic cell suspension culture. Four types of the examined explants, showed significant differences of embryogenic ability; hypocotyl and petiole explants produced the most and the least number of embryos, respectively